Here's why it's premature to say that Ebola has been "cured"

A mother and son who have recovered from Ebola

Aug. 16, 2019 12:37 PM PT

Amid a year-long Ebola outbreak that has no end in sight, this week’s headlines were unusually upbeat:

“Ebola is now curable,” one proclaimed.

“Ebola has finally been cured, say scientists,” announced another.

“Ebola ‘no longer incurable’ as Congo trial finds drugs boost survival,” a third promised.

On Monday, officials at the World Health Organization and the National Institutes of Health announced that two experimental Ebola medications saved about 90% patients who were treated early. The results were so impressive that the drugs will be offered to all patients sickened in the current outbreak.

“From now on, we will no longer say that Ebola is incurable,” said Jean-Jacques Muyembe, who helped run the trial as director general of the National Institute for Biomedical Research in the Democratic Republic of the Congo.

It was welcome news, to be sure. But to many experts who fight infectious diseases, the announcement was seen as overreaching — and even misleading. Here’s why.

What did the studies actually find?

The clinical trial tested four experimental Ebola treatments in 681 patients over the past nine months. The two that were most successful — REGN-EB3 and mAb-114 — are antibody cocktails administered through an IV.

Preliminary results with 499 patients show that among patients who were given REGN-EB3, 71% survived. So did 66% of those treated with mAb-114. (Survival rates were even better — 94% and 89%, respectively — for patients who for had low viral loads, likely a sign that they sought treatment soon after they were infected.)

Experts say those numbers are outstanding considering that, if left untreated, Ebola is fatal about 70% of the time. In addition, both drugs performed significantly better than the medications in the trial. Only 47% of patients who received remdesivir survived their illness, along with 51% of those who got ZMapp. (Among the subset of patients who began treatment with lower viral loads, the survival rate was 67% with remdesivir and 76% with ZMapp.)

That’s great, but do most victims really seek treatment early?

No. For a variety of reasons, many people will delay testing and treatment, and others will never come forward. “For them, it certainly isn’t a cure,” said Lawrence O. Gostin, who directs the O’Neill Institute for National and Global Health Law at Georgetown and served on several review commissions following the epidemic that ended in 2016.

The epicenter of the current outbreak straddles two conflict-ridden provinces of eastern Congo, where insurgents have launched attacks on medical workers and cultivated conspiracy theories about the disease. As a result, many families have hidden infected relatives in their homes. Only a small percentage of Ebola patients have made their way to treatment centers, and an even smaller number have arrived before the disease’s final stages.

The new drugs would be excellent in wealthy countries, where medical care is easily accessible and health officials are trusted. But those are not the places where most outbreaks take root.

“Even a perfect treatment within the hospital setting is a very, very small slice of the solution,” said Sheila Davis, the chief executive of Partners in Health, who led the organization’s response to the 2014 Ebola outbreak in West Africa. “The battle is before that stage. We’re not addressing other key issues that are making this epidemic drag on.”

Medically speaking, have researchers beaten the virus?

That depends on whom you ask. The trial was relatively small, and some patients still died.

“The term ‘cure’ means ridding the body of infection, and fully recovering to the state of health before the Ebola infection,” Gostin said. In his view, declaring a cure was “certainly overstated.”

Some survivors of the West Africa outbreak appeared to shed the Ebola virus from their bloodstream, but small amounts remained in other bodily fluids. Many survivors also experienced long-term complications that drastically altered their quality of life.

Those are two reasons why Muyembe’s comments missed the mark, said Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security.

“The word ‘cure’ is not a good one. ‘Treatment’ is better,” she said. “It’s very good news that people are surviving their infections. But we’ll have to see if they have any manifestations of the disease down the road.”

Is there a downside to calling this a cure?

It’s critical that the messages coming from health officials are honest and transparent. If authorities over-promise, trust in them can erode and patients who need their help won’t seek it.

On the other hand, if people get word of these treatment success stories, it might encourage them to see a doctor sooner, when their chances of recovery are better.

“The difference between ‘You’ll probably die whether you come into care or not’ and ‘If you come early into care, you’ll likely live through Ebola’ is a huge difference for health communication purposes,” said Matthew Kavanagh, a health policy expert at Georgetown.

That was certainly the case with AIDS. When antiretroviral therapy was shown to be effective in the U.S., people living with HIV more readily accepted testing and treatment.

“Offering hope for patients is a game-changer, in terms of bringing them into testing and treatment,” Gostin said. “AIDS proved that.”

So is Ebola ‘no longer incurable’ after all?

Most experts agree that it’s more accurate to say that Ebola is treatable, not curable.

Muyembe’s declaration has “been greeted with a lot of fanfare, and there’s good reason for that,” said Josh Michaud, the associate director of global health policy at the Kaiser Family Foundation in Washington. But he said much more clinical trial evidence will be needed to earn FDA approval, “let alone discussing whether or not they cure.”